The invention concerns a method for preparation of respiratory air of an oxygen air mixture with the addition of substantially pure oxygen gas into air to be inhaled by organisms, in particular human beings, and having a device for physical exercise during inhalation. This type of respiratory air preparation using substantially pure or purely ionized oxygen is primarily used, with great success, for elderly people having low nominal arterial oxygen partial pressure (pO.sub.2) to permanently increase this nominal pO.sub.2 (the principle of Ardennen-O.sub.2, multi-step therapy).
In the conventional method, an oxygen-air mixture is administered to the individual to be supplied with the oxygen-air mixture using a device providing oxygen. The oxygen volume fraction of the oxygen-air mixture to be prepared is set, as a constant time-independent value, at the device providing the oxygen. In particular, oxygen pressure vessels, central oxygen supply installations, devices for the extraction of oxygen through the decomposition of oxygen-rich chemicals, oxygen separation systems having membranes or the like are thereby utilized as the oxygen delivering device. The air mixture having increased oxygen content is applied using breathing masks, nose probes, open applicators or the like.
These conventional methods for preparing respiratory air of an oxygen-air mixture have the following disadvantages. Since the oxygen volume fraction of the oxygen-air mixture to be prepared is set as a fixed quantity at the device delivering the oxygen, the constant oxygen intake is independent of changeable quantities influencing the individual being supplied with the oxygen-air mixture. These quantities are e.g. a changing physical power output of the person being supplied with oxygen. In addition, difficult and time consuming investigations must be initiated to determine the percentage of oxygen volume fraction in the oxygen-air mixture to be prepared in dependence on the physiologically constant quantities of the person being supplied with the oxygen-air mixture, e.g. age, gender, size, weight, physical condition and the like. Adjustment to the instantaneous power being expended by the person supplied with the oxygen-air mixture and of the oxygen fraction of the oxygen-air mixture does not occur or, if at all, in a very poor fashion through manual adjustment.